Apparatus for measuring optical density in situ

Abstract

A device for measuring in situ, the optical density of a sample in a medium, in which the immersed sample has a main part with a slot at one end. A mobile part can be lodged in this slot. This mobile part has an open chamber which moves with the mobile part into the slot. This open chamber will contain a sample and will be aligned with an optical device in the housing, when moved into the slot. The mobile part and open chamber are, therefore, movable between an open position in which the medium to be studied circulates in the chamber, to a closed position when the mobile part is lodged in the slot whereat the open chamber is isolated from the medium to be studied. Measurement is carried out while the device is in the closed position by measuring the optical density of the isolated medium.

What is claimed is: 
     
       1. A device for measuring the optical density in situ of a medium comprising: a main part forming the body of the device, a housing being provided in the main part, the housing being located in the medium;   a movable part which can be housed in said housing and in which an open cavity is provided, the cavity being open to the outside of the movable part via at least two opposite orifices;   optical means in the main part on both sides of the housing for conducting a light flux from a source to a light analyzer through optical surfaces located on both sides of the housing; and   means for shifting the movable part from an open position in which the medium to be studied circulates freely in the cavity of the movable part and the housing to a closed position in which the movable part is positioned within the housing of the main part, such that an interior of the housing, the cavity and contents thereof are isolated from the medium, the contents of the cavity constituting the sample of the medium to be analyzed, on which sample the measurement will be performed, the optical means being aligned with the orifices of the movable part when the movable part is in the closed position such that the light flux passes through the contents of the cavity and the contents of the cavity are isolated form the medium.   
     
     
       2. The device according to claim 1, further comprising means for calibrating intensity of the light flux and means for cleaning the optical surfaces. 
     
     
       3. The device according to claim 2, wherein the calibration means comprises at least one optical bar of known characteristics placed at least momentarily in the optical path of the light flux. 
     
     
       4. The device according to claim 3, wherein the calibration means comprises a plurality of calibration bars having different transmission coefficients. 
     
     
       5. The device according to claims 3 or 4, wherein the calibration bars are placed in the movable part and are movable therewith from a position in the optical path of the light flux to a position out of said optical path. 
     
     
       6. The device according to claim 2, wherein the cleaning means comprises at least one of scrapers and brushes place on the movable part to clean optical surfaces of the main part, and further comprising at least one of scrapers and brushes placed on the main part to clean optical surfaces of the movable part. 
     
     
       7. The device according to claim 1 or 2, wherein the device comprises elements that are resistant to sterilization temperature. 
     
     
       8. The device according to claim 1 or 2, wherein the means for shifting the movable part contains a rotation rod attached to the movable part and a motor for rotation of said rod. 
     
     
       9. The device according to claim 1 or 2, wherein the optical means comprises a bundle of bifurcated fibers connecting the housing to the source and the light analyzer, and the optical means comprises at least one reflector situated on the surface of the housing facing an end of the fiber bundle. 
     
     
       10. The device according to claim 1, wherein the movable part is a disk, the bases of which are inscribed in generally a circle and the thickness of which is equal to the width of a recess close to one end of the main part, the recess being generally perpendicular to the longitudinal axis of the main part and the recess constituting the housing. 
     
     
       11. The device according to claim 10, wherein the cavity of the movable part has an axis of symmetry generally perpendicular to the bases of the disk, which cavity is open to the outside via the two orifices which generally have circular sections. 
     
     
       12. The device according to claim 10, wherein the cavity provided in the movable part is a sector of the movable part. 
     
     
       13. The device according to claim 1, wherein the means for shifting is mounted off-center to the movable body and the means for shifting moves the movable body in an eccentric path.